regExp.H

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/*---------------------------------------------------------------------------*\
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License
    This file is part of OpenFOAM.

    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

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    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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    for more details.

    You should have received a copy of the GNU General Public License
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Class
    Foam::regExp

Description
    Wrapper around POSIX extended regular expressions.

SeeAlso
    The manpage regex(7) for more information about POSIX regular expressions.
    These differ somewhat from @c Perl and @c sed regular expressions.

SourceFiles
    regExp.C

\*---------------------------------------------------------------------------*/

#ifndef regExp_H
#define regExp_H

#include <regex.h>
#include <string>

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{

// Forward declaration of classes
class string;
template<class T> class List;

/*---------------------------------------------------------------------------*\
                           Class regExp Declaration
\*---------------------------------------------------------------------------*/

class regExp
{
    // Private data

        //- Precompiled regular expression
        mutable regex_t* preg_;

    // Private member functions

        //- Disallow default bitwise copy construct
        regExp(const regExp&);

        //- Disallow default bitwise assignment
        void operator=(const regExp&);

public:

        //- Is character a regular expression meta-character?
        //  any character: '.' \n
        //  quantifiers: '*', '+', '?' \n
        //  grouping: '(', '|', ')' \n
        //  range: '[', ']' \n
        //
        //  Don't bother checking for '{digit}' bounds
        inline static bool meta(char c)
        {
            return
            (
                (c == '.')                           // any character
             || (c == '*' || c == '+' || c == '?')   // quantifiers
             || (c == '(' || c == ')' || c == '|')   // grouping/branching
             || (c == '[' || c == ']')               // range
            );
        }


    // Constructors

        //- Construct null
        regExp();

        //- Construct from character array, optionally ignoring case
        regExp(const char*, const bool ignoreCase=false);

        //- Construct from std::string (or string), optionally ignoring case
        regExp(const std::string&, const bool ignoreCase=false);

    // Destructor

        ~regExp();


    // Member functions

    //- Access

        //- Return true if a precompiled expression does not exist
        inline bool empty() const
        {
            return !preg_;
        }

        //- Does a precompiled expression exist?
        inline bool exists() const
        {
            return preg_ ? true : false;
        }

        //- Return the number of (groups)
        inline int ngroups() const
        {
            return preg_ ? preg_->re_nsub : 0;
        }


    //- Editing

        //- Compile pattern into a regular expression, optionally ignoring case
        void set(const char*, const bool ignoreCase=false) const;

        //- Compile pattern into a regular expression, optionally ignoring case
        void set(const std::string&, const bool ignoreCase=false) const;


        //- Release precompiled expression.
        //  Returns true if precompiled expression existed before clear
        bool clear() const;


    //- Searching

        //- Find position within string.
        //  Returns the index where it begins or string::npos if not found
        std::string::size_type find(const std::string& str) const;

        //- Return true if it matches the entire string
        //  The begin-of-line (^) and end-of-line ($) anchors are implicit
        bool match(const std::string&) const;

        //- Return true if it matches and sets the sub-groups matched
        //  The begin-of-line (^) and end-of-line ($) anchors are implicit
        bool match(const string&, List<string>& groups) const;

        //- Return true if the regex was found in within string
        bool search(const std::string& str) const
        {
            return std::string::npos != find(str);
        }


    // Member Operators

        //- Assign and compile pattern from a character array
        //  Always case sensitive
        void operator=(const char*);

        //- Assign and compile pattern from string
        //  Always case sensitive
        void operator=(const std::string&);

};


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

} // End namespace Foam

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

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